GS-4012F/4024 User’s Guide

CHAPTER 20

Queuing Method

This chapter introduces the queuing methods supported.

20.1 Overview

Queuing is used to help solve performance degradation when there is network congestion. Use the Queuing Method screen to configure queuing algorithms for outgoing traffic. See also Priority Queue Assignment in Switch Setup and 802.1p Priority in Port Setup for related information.

Queuing algorithms allow switches to maintain separate queues for packets from each individual source or flow and prevent a source from monopolizing the bandwidth.

The switch has eight physical queues, Q0 to Q7. Q7 has the highest priority and Q0 has the lowest.

Table 40 Physical Queue Priority

QUEUE

PRIORITY

 

 

 

Q7

8

(Highest)

 

 

 

Q6

7

 

 

 

 

Q5

6

 

 

 

 

Q4

5

 

 

 

 

Q3

4

 

 

 

 

Q2

3

 

 

 

 

Q1

2

 

 

 

 

Q0

1

(Lowest)

 

 

 

20.1.1 Strict Priority Queuing (SPQ)

Strict Priority Queuing (SPQ) services queues based on priority only. As traffic comes into the switch, traffic on the highest priority queue, Q3 is transmitted first. When that queue empties, traffic on the next highest-priority queue, Q2 is transmitted until Q2 empties, and then traffic is transmitted on Q1 and so on. If higher priority queues never empty, then traffic on lower priority queues never gets sent. SPQ does not automatically adapt to changing network requirements.

Chapter 20 Queuing Method

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